Electrical receiver



Nov. 13, 1928.

H. M. WILLIAMSON ELECTRICAL RECEIVER Filed July 12, 1925 IN V EN TOR. Henr /Z M/l/amson,

A TTORNE Y.

\ latented Nov. 13, 1928.

- UNITED STATES IERRY u.

PATENT OFFICE.

WILLIAMSON, OF OHICAGO,,ILLINOIS, ASSIGNOR TO JOHNSON-WILLIAMSON LABORATORIES, INCORPORATED, A CORPORATION OF ILLINOIS.

Application filed July 12,

The invention relates to receivers which operate to translate electrical undulations into audible sound waves, one object thereof being to producean exceedingly sens tive 1n- 5 strument which will propagate sound waves in a clear and distinct manner, whereby 11steners will hear reproduced sounds the same as if they emanated from an original source. It is a further ob'ect of the invention to produce a loud-spea ing receiver in which the vibrating element may be able to effectively vibrate, without striking other parts and' thereby producing what is known as chattering a phenomenon which overwhelms ar 15 ticulate speech when the current 1s strong enough to produce it. Attempts have been made to eliminate this defect which-is inherent in ordinary loud speakers, by providing a considerable space between the armature and the magnet, but the increase of distance between the-two elements lessened the mag netic. attraction in proportion to the square of the distance, and necessitated utilization of a current all out of pro ortion to the work performed in vibrating e armature.

The device herein described and shown, is so constructed as to prevent excessive vibrations of the armature, andto admit of the use of a small amount of electrical energy while roducing a strong magnetic action to therecompel the armature and its associated acoustical elements to operate with a high de ee ofv efliciency.

' e invention will be fully understood if reference is made to the accompanying drawin in which'- igure 1 is a plan view of the receiver; Figure 2 is a view of the receiver in elevation;

40 Figure 3 shows a'spring usedin the receiver; a f

Figure 4 is a view of the armature; Figure 5 is a sectional view showing the electro-magnets, the armature and the spring;

Figures 6 and 7 are views showlng the needle of a phono aph applied to the armature, whereby e "acoustical elements of the phonograph may be used tions to the air.

The new device embodies, as its principal; elements, a casing 1, a'permanent magnet 2 having pole-pieces 3, a spring 4 having a,

to impart the vibra-' and repellent forces, greatl 1923 Serial No. 650,981.

notch, mounted on cross-pieces 5, an armature 6, notched on both sides, carried by said spring and extending between said polepieces, and two electro-magnets 7 arranged one at each end of said armature. The spring acts torsionally, and is strong enough to normally retain the armature in substantially a median position between the pole-pieces, although it allows said armature to vibrate with suificient amplitude to produce the desired sound waves, the object, as already stated, being to prevent contact with the polepieces. The interlocking joint between the spring and the armature produces a rigid entity whose parts are relatively immovable.

The armature, while extending through the electro-magnets, is slightly spaced therefrom in order that it-may oscillate between the pole-pieces, the said spring being determinative of its center of oscillation.

The magnet 2 and the pole-pieces 3 coincide, and the pole-pieces are, therefore, subjected to the action of maximum lines of force. Also, the ends of the spring are unad- 'ustably fixed to the cross-pieces 5, the result eing avoidance of chattering due to loosening of the parts by the rapid and strong vi- 30 brations of the armature, asheretofore experienced in the operation of other instru- 'nients. Furthermore, the continuity of the springcompels the armature to truly oscillate in a well-defined single plane, whereby contact thereof with the pole pieces of the instrument is avoided.

The windings of the electro-magnets may be in series 'or in parallel, but in either arrangement a currenttof alternating or interrupted character will effectuate reversals in the polarity of the electro-magnets which are so wound as to alternately cause the armature to be attracted in o posite directions at its oppositeends upon t e occurrence of a single impulse, and, at the same time, tobe repelled in like manner. Combining theseattractiveimproves the acoustical efficiencyof the instrument, and also increases the sensitiveness in such degree that the electrical energy required to produce loud speaking, is very little.

The needle 8, Figure 6, is shown as ap lied to a slot 9 inwhich its tip rests, whereby it may move laterally and partake of the vibrations of the armature. The phonograph would, in this instance, employ records-having lateral undulations, but would be-otherwise connected with the armature if another type of record were used. Figure 7 shows a hole 9, but a slot is preferable.

Having thus described my invention, what I claim is:

1 1. An electrical receiver including in combination a magnet, pole pieces for said magnet, an armature element disposed between said pole pieces, a continuous torsional spring, fixed at its ends, constituting a mounting for said armature element I and of sufiicient strength to normally retain said armature element in substantially a median position proximate ends and provided with pole pieces, and windings for receiving current to cause said armature to be attracted and re elled by said magnet.

2. e combination with a magnet having airs of separated pole pieces mounted on said ends,

an armature extending between said pole pieces,-and a torsional spring mounting for said armature, said pole pieces being disposed within the physical limits of said ma net, and having contact with substantially t e entire inner'areas of said ends.

In testimofiawhereof I aflix my signature.

, NRY M. WILLIAMSON. 

